We know this because there is a broad counterfactual law in physics that says ‘it is impossible to build a perpetual motion machine’.
Well, it’s not really a law as such , because it’s an outcome of more general laws such as the second law of thermodynamics. And since the second law is a macroscopic law, it’s only macroscopic perpetual motion machines that are impossible. Any stable atom is a little PM machine.
Because the claim that energy is bounded from below is itself a counterfactual principle
Sure, but that doesn’t mean it isn’t a physics principle, or needs some novel explanation. Any deterministic law makes a bunch of things impossible....the determined outcomes happens of necessity, everything else is impossible.
The reason for this is that the second law is also a counterfactual principle which cannot be expressed in the PC.
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As it stands, reconciling the irreversible second law with reversible dynamical laws in the PC is impossible without resorting to some sort of averaging or coarse-graining
I can think of two other solutions:
The 2LT is only an approximation, and things actually do cycle round to a low entropy state after a sufficiently long period.
Reversible microphysical laws are only special cases of irreversible macrophysical laws.
Well, it’s not really a law as such , because it’s an outcome of more general laws such as the second law of thermodynamics. And since the second law is a macroscopic law, it’s only macroscopic perpetual motion machines that are impossible. Any stable atom is a little PM machine.
Sure, but that doesn’t mean it isn’t a physics principle, or needs some novel explanation. Any deterministic law makes a bunch of things impossible....the determined outcomes happens of necessity, everything else is impossible.
!!!!!!!
I can think of two other solutions:
The 2LT is only an approximation, and things actually do cycle round to a low entropy state after a sufficiently long period.
Reversible microphysical laws are only special cases of irreversible macrophysical laws.